Recombinant High-Density Lipoprotein Formulations

Recombinant high-density lipoprotein targeted delivery of celastrol to promote foam cells lipophagy against early atherosclerosis

INTRODUCTION

Atherosclerosis serving as the main underlying factor of cardiovascular disease (CVD) remains the primary cause of mortality and morbidity globally, while the deposition of massive cholesterol in macrophage-derived foam cells exerts pivotal roles in the occurrence and progression of atherosclerosis. Celastrol (CEL) is a bioactive ingredient owning potent capability to modulate lipid metabolism, whereas the poor bioavailability and potential toxicity limit its clinical application.

OBJECTIVES

This study aims to design a CEL-loaded recombinant high-density lipoprotein (rHDL) delivery platform for active targeting, which may effectively promote lipid degradation in foam cells and reversely transport excessive cholesterol to the liver for metabolism in time.

METHODS

The rHDL loaded with CEL (CEL-rHDL) was prepared by the thin film dispersion method. Then the anti-atherosclerotic efficacy and targeted delivery to foam cells of atherosclerotic lesions were verified both in vitro and in vivo. RNA-sequence was applied to reveal the potential mechanism against early atherosclerosis, which was further validated through several molecular biology experiments.

RESULTS

The prepared CEL-rHDL increased the targeting efficiency to foam cells of atherosclerotic lesions, mitigated its off-target toxicity, and improved anti-atherosclerotic efficacy. Importantly, CEL-rHDL decreased lipid storage in foam cells by triggering lipophagy via the activation of Ca2+/CaMKKβ/AMPK/mTOR signaling pathway and reverse cholesterol transport (RCT).

CONCLUSION

A combination of hypolipidemic chemo-intervention with rHDL participated specific and reverse delivery may offer a promising strategy for biocompatible treatment of early atherosclerosis.

The Pleiotropic Effects of Lipid-Modifying Interventions: Exploring Traditional and Emerging Hypolipidemic Therapies

Atherosclerotic cardiovascular disease poses a significant global health issue, with dyslipidemia standing out as a major risk factor. In recent decades, lipid-lowering therapies have evolved significantly, with statins emerging as the cornerstone treatment. These interventions play a crucial role in both primary and secondary prevention by effectively reducing cardiovascular risk through lipid profile enhancements. Beyond their primary lipid-lowering effects, extensive research indicates that these therapies exhibit pleiotropic actions, offering additional health benefits. These include anti-inflammatory properties, improvements in vascular health and glucose metabolism, and potential implications in cancer management. While statins and ezetimibe have been extensively studied, newer lipid-lowering agents also demonstrate similar pleiotropic effects, even in the absence of direct cardiovascular benefits. This narrative review explores the diverse pleiotropic properties of lipid-modifying therapies, emphasizing their non-lipid effects that contribute to reducing cardiovascular burden and exploring emerging benefits for non-cardiovascular conditions. Mechanistic insights into these actions are discussed alongside their potential therapeutic implications.

Protective and Regenerative Effects of Reconstituted HDL on Human Rotator Cuff Fibroblasts under Hypoxia: An In Vitro Study

Hypoxia and hypo-high-density lipoproteinemia (hypo-HDLemia) are proposed risk factors for rotator cuff tear. HDL is recognized for its potential benefits in ischemia-driven angiogenesis and wound healing. Nevertheless, research on the potential benefits of reconstituted HDL (rHDL) on human rotator cuff fibroblasts (RCFs) under hypoxia is limited. This study investigates the cytoprotective and regenerative effects of rHDL, as well as N-acetylcysteine (NAC), vitamin C (Vit C), and HDL on human RCFs under hypoxic conditions. Sixth-passage human RCFs were divided into normoxia, hypoxia, and hypoxia groups pretreated with antioxidants (NAC, Vit C, rHDL, HDL). Hypoxia was induced by 1000 µM CoCl2. In the hypoxia group compared to the normoxia group, there were significant increases in hypoxia-inducible factor-1α (HIF-1α), heme oxygenase-1 (HO-1), and Bcl-2/E1B-19kDa interacting protein 3 (BNIP3) expressions, along with reduced cell viability, elevated reactive oxygen species (ROS) production, apoptosis rate, expressions of cleaved caspase-3, cleaved poly ADP-ribose polymerase-1 (PARP-1), vascular endothelial growth factors (VEGF), and matrix metalloproteinase-2 (MMP-2), as well as decreased collagen I and III production, and markedly lower cell proliferative activity (p ≤ 0.039). These responses were significantly mitigated by pretreatment with rHDL (p ≤ 0.046). This study suggests that rHDL can enhance cell proliferation and collagen I and III production while reducing apoptosis in human RCFs under hypoxic conditions.

Beneficial effects of high-density lipoprotein (HDL) on stent biocompatibility and the potential value of HDL infusion therapy following percutaneous coronary intervention

Several epidemiological studies have shown a clear inverse relationship between serum levels of high-density lipoprotein cholesterol (HDL-C) and the risk of atherosclerotic cardiovascular disease (ASCVD), even at low-density lipoprotein cholesterol levels below 70 mg/dL. There is much evidence from basic and clinical studies that higher HDL-C levels are beneficial, whereas lower HDL-C levels are detrimental. Thus, HDL is widely recognized as an essential anti-atherogenic factor that plays a protective role against the development of ASCVD. Percutaneous coronary intervention is an increasingly common treatment choice to improve myocardial perfusion in patients with ASCVD. Although drug-eluting stents have substantially overcome the limitations of conventional bare-metal stents, there are still problems with stent biocompatibility, including delayed re-endothelialization and neoatherosclerosis, which cause stent thrombosis and in-stent restenosis. According to numerous studies, HDL not only protects against the development of atherosclerosis, but also has many anti-inflammatory and vasoprotective properties. Therefore, the use of HDL as a therapeutic target has been met with great interest. Although oral medications have not shown promise, the developed HDL infusions have been tested in clinical trials and have demonstrated viability and reproducibility in increasing the cholesterol efflux capacity and decreasing plasma markers of inflammation. The aim of the present study was to review the effect of HDL on stent biocompatibility in ASCVD patients following implantation and discuss a novel therapeutic direction of HDL infusion therapy that may be a promising candidate as an adjunctive therapy to improve stent biocompatibility following percutaneous coronary intervention.

ApoA-I deficiency increases cortical amyloid deposition, cerebral amyloid angiopathy, cortical and hippocampal astrogliosis, and amyloid-associated astrocyte reactivity in APP/PS1 mice

Background

Alzheimer’s disease (AD) is defined by amyloid beta (Aβ) plaques and neurofibrillary tangles and characterized by neurodegeneration and memory loss. The majority of AD patients also have Aβ deposition in cerebral vessels known as cerebral amyloid angiopathy (CAA), microhemorrhages, and vascular co-morbidities, suggesting that cerebrovascular dysfunction contributes to AD etiology. Promoting cerebrovascular resilience may therefore be a promising therapeutic or preventative strategy for AD. Plasma high-density lipoproteins (HDL) have several vasoprotective functions and are associated with reduced AD risk in some epidemiological studies and with reduced Aβ deposition and Aβ-induced inflammation in 3D engineered human cerebral vessels. In mice, deficiency of apoA-I, the primary protein component of HDL, increases CAA and cognitive dysfunction, whereas overexpression of apoA-I from its native promoter in liver and intestine has the opposite effect and lessens neuroinflammation. Similarly, acute peripheral administration of HDL reduces soluble Aβ pools in the brain and some studies have observed reduced CAA as well. Here, we expand upon the known effects of plasma HDL in mouse models and in vitro 3D artery models to investigate the interaction of amyloid, astrocytes, and HDL on the cerebrovasculature in APP/PS1 mice.

Methods

APP/PS1 mice deficient or hemizygous for Apoa1 were aged to 12 months. Plasma lipids, amyloid plaque deposition, Aβ protein levels, protein and mRNA markers of neuroinflammation, and astrogliosis were assessed using ELISA, qRT-PCR, and immunofluorescence. Contextual and cued fear conditioning were used to assess behavior.

Results

In APP/PS1 mice, complete apoA-I deficiency increased total and vascular Aβ deposition in the cortex but not the hippocampus compared to APP/PS1 littermate controls hemizygous for apoA-I. Markers of both general and vascular neuroinflammation, including Il1b mRNA, ICAM-1 protein, PDGFRβ protein, and GFAP protein, were elevated in apoA-I-deficient APP/PS1 mice. Additionally, apoA-I-deficient APP/PS1 mice had elevated levels of vascular-associated ICAM-1 in the cortex and hippocampus and vascular-associated GFAP in the cortex. A striking observation was that astrocytes associated with cerebral vessels laden with Aβ or associated with Aβ plaques showed increased reactivity in APP/PS1 mice lacking apoA-I. No behavioral changes were observed.

Conclusions

ApoA-I-containing HDL can reduce amyloid pathology and astrocyte reactivity to parenchymal and vascular amyloid in APP/PS1 mice.

Electronic supplementary material

The online version of this article (10.1186/s13195-019-0497-9) contains supplementary material, which is available to authorized users.

Carboxyl-Terminal Cleavage of Apolipoprotein A-I by Human Mast Cell Chymase Impairs Its Anti-Inflammatory Properties

OBJECTIVE

Apolipoprotein A-I (apoA-I) has been shown to possess several atheroprotective functions, including inhibition of inflammation. Protease-secreting activated mast cells reside in human atherosclerotic lesions. Here we investigated the effects of the neutral proteases released by activated mast cells on the anti-inflammatory properties of apoA-I.

APPROACH AND RESULTS

Activation of human mast cells triggered the release of granule-associated proteases chymase, tryptase, cathepsin G, carboxypeptidase A, and granzyme B. Among them, chymase cleaved apoA-I with the greatest efficiency and generated C-terminally truncated apoA-I, which failed to bind with high affinity to human coronary artery endothelial cells. In tumor necrosis factor-α-activated human coronary artery endothelial cells, the chymase-cleaved apoA-I was unable to suppress nuclear factor-κB-dependent upregulation of vascular cell adhesion molecule-1 (VCAM-1) and to block THP-1 cells from adhering to and transmigrating across the human coronary artery endothelial cells. Chymase-cleaved apoA-I also had an impaired ability to downregulate the expression of tumor necrosis factor-α, interleukin-1β, interleukin-6, and interleukin-8 in lipopolysaccharide-activated GM-CSF (granulocyte-macrophage colony-stimulating factor)- and M-CSF (macrophage colony-stimulating factor)-differentiated human macrophage foam cells and to inhibit reactive oxygen species formation in PMA (phorbol 12-myristate 13-acetate)-activated human neutrophils. Importantly, chymase-cleaved apoA-I showed reduced ability to inhibit lipopolysaccharide-induced inflammation in vivo in mice. Treatment with chymase blocked the ability of the apoA-I mimetic peptide L-4F, but not of the protease-resistant D-4F, to inhibit proinflammatory gene expression in activated human coronary artery endothelial cells and macrophage foam cells and to prevent reactive oxygen species formation in activated neutrophils.

CONCLUSIONS

The findings identify C-terminal cleavage of apoA-I by human mast cell chymase as a novel mechanism leading to loss of its anti-inflammatory functions. When targeting inflamed protease-rich atherosclerotic lesions with apoA-I, infusions of protease-resistant apoA-I might be the appropriate approach.

Revising the high-density lipoprotein targeting strategies - insights from human and preclinical studies

In recent years, the high-density lipoprotein (HDL) hypothesis has been challenged. Several completed randomized clinical trials continue to fall short in demonstrating HDL, or at least HDL-cholesterol (HDL-C) levels, as being a consistent target in the prevention of cardiovascular diseases. However, population studies and findings in lipid modifying trials continue to strongly support HDL-C as a superb risk predictor. It is increasingly evident that the complexity of HDL metabolism confounds the use of HDL-C concentration as a unified target. However, important insights continue to emerge from the post hoc analyses of recently completed (i) fibrate-based FIELD and ACCORD trials, including the unexpected beneficial effect of fibrates in microvascular diseases, (ii) the niacin-based AIM-HIGH and HPS2-THRIVE studies, (iii) recombinant HDL-based as well as (iv) the completed CETP inhibitor-based trials. These together with on-going mechanistic studies on novel pathways, which include the unique roles of microRNAs, post-translational remodeling of HDL and novel pathways related to HDL modulators will provide valuable insights to guide how best to refocus and redesign the conceptual framework for selecting HDL-based targets.

HDL--is it too big to fail?

The HDL hypothesis has suffered damage in the past few years. Clinical trials have shown that raising HDL cholesterol levels does not improve cardiovascular disease (CVD) outcomes. In addition, Mendelian randomization studies have shown that DNA variants that alter HDL cholesterol levels in populations are unrelated to incident CVD events. Balancing this deluge of negative data are substantial basic science data supporting the concept that raising HDL cholesterol levels reduces CVD risk. Also, functionally relevant HDL subfractions might be more important determinants of risk than overall HDL cholesterol levels. But, while wobbly, the HDL hypothesis is still standing, seemingly too big to fail owing to past intellectual, economic and psychological investments in the idea.

Normalization using a tagged-internal standard assay for analysis of antibody arrays and the evaluation of serological biomarkers for liver disease

For minimizing systemic experimental variation in the analysis of antibody array data, we developed a novel median-centered/IgM-tagged-internal standard (TIS) assay normalization using median-centering and TIS assay-based determination of serum IgM concentrations. We evaluated five normalization methods by analyzing correlation coefficients and coefficients of variation for six serum proteins using human serum samples from normal controls (n=25) and patients with liver cirrhosis (n=25) or hepatocellular carcinoma (HCC; n=29). Median-centered normalization improved correlation coefficients, while IgM-based normalizations improved coefficients of variation. The TIS assay was more efficient, economical, and reproducible for determining IgM concentrations than enzyme-linked immunosorbent assay. Additionally, we normalized antibody array data for six serum proteins using the median-centered/IgM-TIS assay, and evaluated serum biomarkers through distribution analysis of normalized fluorescence intensities and receiver operating characteristic analyses for the diagnosis of liver cirrhosis and HCC. Apolipoprotein A-1 and a combination of alpha-fetoprotein and C-reactive protein were determined to be potential serological biomarkers for liver cirrhosis and HCC, respectively. Thus, median-centered/IgM-TIS assay normalization is a useful approach for analyzing antibody array data and evaluating serological biomarkers for the diagnosis of liver disease or cancers.

Clinical Trials Update AHA Congress 2010

The clinical trials described in this article were presented at the Late Breaking Trials and the Clinical Science: Clinical Reports sessions of the American Heart Association Congress held in November 2010 in Chicago. The sessions and topics chosen for this article reflect the scope of interest of Cardiovascular Drugs and Therapy. The presentations should be considered preliminary, as further analyses may be done, which could alter the final publication of the results of these studies. PROTECT (ProBNP Outpatient Tailored Chronic Heart Failure Therapy) was designed to test the hypothesis that adjustment of intensity of chronic heart failure (HF) therapy on the basis of NT-proBNP plasma level monitoring would improve outcomes. The results provided some support of this concept, but needs further evaluation in larger, blinded trials. REVEAL (Reduction of Infarct Expansion and Ventricular Remodeling with erythropoietin after large myocardial infarctions) evaluated in the clinical setting of ischemia-reperfusion following STEMI that erythropoietin could salvage ischemic myocardium. The results did not show a reduction in infarct size, but, in contrast, an increase in adverse event rates in the erythropoietin group. GRAVITAS (Gauging Responsiveness with a VerifyNow assay-Impact on Thrombosis and Safety trial) investigated the effect of a standard vs. high maintenance clopidogrel dose in patients with stable myocardial ischemia or NSTEMI and drug-eluting stent insertion. Patients with high PRU values as determined by VerfyNow assay were randomized to 75 mg or 150 mg clopidogrel daily. The study did not show a significant difference in primary event rate between both groups. The Cholesterol Treatment Trialists' Collaboration Studies group evaluated the concept proposed in the JUPITER study that HDL levels on statin treatment may not provide useful prognostic information. The CTTC in a large sample size of statin-treated patients observed, on the contrary, a significantly increased risk of CV events, even in patients with low LDL cholesterol levels. DEFINE (Determining the Efficacy and Tolerability of CETP inhibition with Anacetrapib) evaluated possible safety aspects with the CETP inhibitor anacetrapib (increase in blood pressure). The study did not show adverse safety aspects, but significantly reduced LDL cholesterol and increased HDL cholesterol levels. ASSERT, a phase 2 dose-ranging study, investigated whether RVX-208 would increase Apo-A1 production. Apo-A1 may induce cholesterol efflux from macrophages and facilitate atherosclerosis regression. The study did not meet its primary endpoint, but significant prominent effects on lipids were found. ASCEND-HF was a large trial of nesiritide in >7000 patients with acute heart failure. The study did not show convincing symptom benefit, but on the other hand did not show harmful effects of nesiritide. EMPHASIS-HF evaluated the long term effects of eplerenone in patients with mild (NYHA class II) heart failure and systolic dysfunction. The study was prematurely ended because of highly significant beneficial effects. CUPID (Calcium Up-regulation by Percutaneous administration of gene therapy In cardiac Disease) is the first human study with gene transfer of SERCA2a (AVV1/SERCA2a: Mydicar). In a small placebo-controlled dose-ranging study in advanced heart failure patients a multiple endpoint analysis provided positive effects of the highest dose on symptomatic, functional and structural efficacy endpoints without adverse effects.